Apparatus and a method for the production of yarn having properties approaching that of ring spun yarn, only at significantly greater speeds and with other significant operational advantages (such as automatic elimination of lint fly or oily waste) has been disclosed in U.S. Pat. No. 4,507,913 and commonly assigned co-pending application Ser. No. 677,487 filed Dec. 3, 1984. This advantageous new procedure for the spinning of yarn has been denoted "vacuum spinning". In the practice of vacuum spinning, an elongated tubular shaft having first and second ends with a through-extending passageway from the first end to the second end is mounted for rotation about an axis. At least a portion of the circumference of the shaft is perforated, and a vacuum source applies a vacuum to the exterior of the shaft as the shaft is rotated about its axis. A sliver or roving is passed into the shaft, and the vacuum causes at least some of the fibers or free ends of fibers passing through the shaft to be drawn toward the shaft perforations, so that they will be caused to rotate with the shaft as the fibers move linearly generally along the axis of rotation. The yarn that is formed is withdrawn from the second end of the shaft.
While vacuum spinning is a generally low maintenance procedure, during the initial start up there are difficulties in threading the fibers through the shaft passageway to the take-up mechanism. The procedure is not self-starting, and typically has been accomplished in the past by using a thread-up wire attached to the end of the fibers and manually pushing and pulling the thread-up wire through the passageway until the fibers were completely through the passageway. Then the fibers were wrapped around a take-up cone, or like take-up mechanism.
According to the present invention a method and apparatus are provided which greatly facilitate the initial threading of a vacuum spinning system elongated hollow shaft. According to the present invention initial threading is provided in an efficient semi-automatic procedure.
According to one aspect of the present invention, initial threading apparatus is provided comprising a cooperating vacuum reservoir having walls, and a vacuum tube having first and second ends. The vacuum reservoir is connected up to a source of vacuum. Means are provided for defining an opening in one of the reservoir walls, and means are provided for mounting the vacuum tube for rotation with respect to the reservoir so that the second end of the tube is movable from a first, inoperative, position wherein it is spaced from the opening, to a second, operative, position wherein it is in operative communication with the opening so that a vacuum is drawn through the tube first end into the reservoir and to the source of vacuum. The axis of rotation of the tube is generally parallel to the axis of rotation of the elongated shaft of the vacuum spinning apparatus, so that when the tube is rotated into its second, operative, position the first end of the tube is immediately adjacent the second end of the elongated shaft so that it sucks the connected fibers within the shaft all the way through to the second end thereof. Preferably means are provided responsive to rotation of the vacuum tube from its first to its second positions for cutting out the vacuum applied to the exterior of the elongated shaft when the vacuum tube is moved toward its second position.
According to the present invention a method is also provided of threading an elongated hollow shaft having a first end and a second end, and a through-extending passageway from the first end to the second end. The method comprises the following steps: (a) Feeding connected fibers into the first end of the passageway. (b) Moving a vacuum source into operative association with the second end of the passageway to suck the connected fibers through the passageway so that a segment of connected fibers extends all the way through the passageway. (c) Moving the vacuum source to an inoperative position wherein it is operatively spaced from the passageway; and (d) bringing the segment of connected fibers into operative association with a take-up mechanism spaced from the second end of the shaft. The elongated hollow shaft has at least a portion of the circumference thereof perforated, and a vacuum source is applied to the exterior of the shaft to draw air through the first end of the shaft and the perforations. The vacuum source is temporarily rendered inactive during the practice of step (b), but is reactivated when step (c) is practiced.
It is the primary object of the present invention to provide an efficient and simple method and apparatus for the initial threading of vacuum spinning apparatus. This and other objects of the invention will become clear from an inspection of the detailed description of the invention, and from the appended claims.